RFI suppression chokes with integral attachment features and extension legs to replace bus bars

ABSTRACT

A choke  10,  for suppressing radio-frequency interference of a brush-type motor, includes a single wire having a portion  15  wound about a coil axis A to define a plurality of coils  14 including two outermost coils  16  and  18.  An attaching structure  20  extends from each outermost coil and is disposed generally transverse with respect to the coil axis. Each attaching structure is constructed and arranged to be inserted through an associated opening in a supporting structure and to be bent so as secure the choke to the supporting structure. An elongated end portion  22  extends from each attaching structure so as to be spaced from and generally parallel to the coil axis. The elongated end portions extend in opposite directions. One of the elongated end portions is constructed and arranged to be directly electrically connected to an electrical connector of a motor and the other of the elongated end portions is constructed and arranged to be in electrical connection with a brush of the motor.

[0001] This application is based on U.S. Provisional Application No.60/227,175, filed Aug. 23, 2000 and claims the benefit thereof forpriority purposes.

FIELD OF THE INVENTION

[0002] This invention relates to d.c. electric motors for automotiveapplications and, more particularly, to a choke having features forimproved mechanical and electrical connection with components of a brushcard assembly.

BACKGROUND OF THE INVENTION

[0003] Typical multi-pole automotive d.c. electric motors use bus barsto conduct current between the electrical connector of the motor andassociated components such as chokes, capacitors, and brushes.Conventional bus bars have to be manufactured and physically attached,supported and connected with the motor. Typically, the bus bars areriveted to the brush card of the motor. The electrical connection isusually achieved using soldered or heat-fused joints.

[0004] Thus, there is a need to reduce the number of electricalconnections required on the motor's brush card, to eliminate costly busbars and to reduce the number of separate mechanical fasteners needed onthe brush card.

[0005] Furthermore, conventionally, wound wire coils or chokes areinstalled close to the brushes of d.c. motors, particularly inautomotive applications. The purpose of the chokes is to suppressradio-frequency interference (RFI) generated by the motor. Generally,the chokes are physically attached to the brush card of the motor usingfixing or fastening techniques that require additional specific parts orprocesses, for example, the ends of the chokes may be soldered toconductors that are riveted to the brush card, the chokes may beinstalled within purpose-designed locations molded into the brush card,and/or clips or other fasteners may be used to attached the chokes.

[0006] Hence, there is also a need to provide secure mechanicalattachment of the choke to the brush card while avoiding the necessityof either a molded brush card or specific fastening components.

SUMMARY OF THE INVENTION

[0007] An object of the present invention is to fulfill the needsreferred to above. In accordance with the principles of the presentinvention, this objective is obtained by providing a choke forsuppressing radio-frequency interference of a brush-type motor. Thechoke includes a single wire having a portion wound about a coil axis todefine a plurality of coils including two outermost coils. An attachingstructure extends from each outermost coil and is disposed generallytransverse with respect to the coil axis. Each attaching structure isconstructed and arranged to be inserted through an associated opening ina supporting structure and to be bent so as secure the choke to thesupporting structure. An elongated end portion extends from eachattaching structure so as to be spaced from and generally parallel tothe coil axis. The elongated end portions extend in opposite directions.One of the elongated end portions is constructed and arranged to bedirectly electrically connected to an electrical connector of a motorand the other of the elongated end portions is constructed and arrangedto be in electrical connection with a brush of the motor.

[0008] In accordance with another aspect of the invention, a brush cardassembly for a d.c. motor includes at least one choke having a portionwound about a coil axis to define a plurality of coils including twooutermost coils, an attaching structure extending from each outermostcoil and being generally transverse with respect to the coil axis. Anelongated end portion extends from each attaching structure so as to bespaced from and generally parallel to the coil axis, the elongated endportions extending in opposite directions. The assembly further includesa brush card having first and second opposing sides and a pair ofopenings through the opposing sides. Each attaching structure isdisposed through an associated opening and bent so as to be adjacent tothe second side, with the wound portion of the choke being disposed onthe first side of the brush card, such that the choke is secured to thebrush card. A brush is mounted on the brush card and is in electricalconnection with one of the elongated end portions. An electricalconnector is mounted on the brush card. The electrical connector has aterminal receiving the other elongated end portion of the choke.

[0009] In accordance with yet another aspect of the invention, a methodof connecting a choke to a brush card assembly is provided. The chokeinclude a portion wound about a coil axis to define a plurality of coilsincluding two outermost coils. An attaching structure extends from eachoutermost coil and is disposed generally transverse with respect to thecoil axis. An elongated end portion extends from each attachingstructure so as to be spaced from and generally parallel to the coilaxis. The elongated end portions extend in opposite directions. Thebrush card assembly includes a brush card having first and secondopposing sides and a pair of openings through the opposing sides. Abrush and an electrical connector are mounted on the brush card. Theelectrical connector has a terminal. The method includes the steps ofinserting each attaching structure through an associated opening, withthe wound portion of the choke being disposed on the first side of thebrush card, bending each attaching structure so as to be adjacent to thesecond side, thereby securing the choke to the brush card, directlyelectrically connecting one of the elongated end portions with theterminal, and electrically connecting the other elongated end portionwith the brush.

[0010] Other objects, features and characteristics of the presentinvention, as well as the methods of operation and the functions of therelated elements of the structure, the combination of parts andeconomics of manufacture will become more apparent upon consideration ofthe following detailed description and appended claims with reference tothe accompanying drawings, all of which form a part of thisspecification.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a perspective view of a choke for a d.c motor providedin accordance with the principles of the invention;

[0012]FIG. 2 is a right end view of the choke of FIG. 1;

[0013]FIG. 3 is view of a front of a brush card assembly of theinvention showing a pair of chokes mounted to a brush card and connectedto terminals of a motor connector; and

[0014]FIG. 4 is a view of the back of brush card assembly of theinvention showing chokes crimped to secure the chokes to the brush card.

DETAILED DESCRIPTION OF THE INVENTION

[0015] Referring to FIG. 1, a choke, generally indicated 10, forsuppressing radio-frequency interference of a brush-type, multi-poled.c. motor, is shown in accordance with the principles of the invention.The choke 10 comprises a single conductive wire 12 having a portion 15wound about a coil axis A to define a plurality of coils 14 includingtwo outermost coils, 16 and 18. The choke 10 includes an attachingstructure, generally indicated at 20 and 20′, extending from each ofoutermost coils 16 and 18, generally transverse with respect to the coilaxis A. An elongated end portion 22 extends from each attachingstructure 20 and 20′ so as to be spaced from and generally parallel tothe coil axis A. The elongated end portions 22 extend in oppositedirections from the attaching structures 20 and 20′ a distancesubstantially equal to a length of the portion 15 wound about the axisA. A center axis B and C of each elongated end portion 22 is disposed ona common plane P.

[0016] In the illustrated embodiment, attaching structure 20 includes afirst portion 24 bent to extend transversely from an associatedelongated end portion 22 and generally along the plane P. A secondportion 26 is bent to extend downwardly and transversely with respect tothe first portion 24. A third portion 28 is bent to extend from thesecond portion 26 so as to be generally parallel with the first portion24, but below plane P. A fourth portion 30 bent to extend upwardly fromthe third portion 28 to the outermost coil 16. The fourth portion 30 isgenerally parallel with respect to the second portion 26.

[0017] As best shown in FIG. 2, attaching structure 20′ includes a firstportion 27 bent to extend downwardly and transversely with respect tothe elongated end portion 22″. A second portion 29 is bent to extendtransversely from the first portion 27 below plane P. A third portion 31bent to extend upwardly from the second portion 29 to the outermost coil18. The third portion 31 is generally parallel with respect to the firstportion 27.

[0018]FIGS. 3 and 4 show the connection of chokes 10 of FIGS. 1 and 2 toa brush card assembly, generally indicated at 32. The brush cardassembly 32 includes a brush card 34 having a first side 36 and anopposing second side 38. An electrical connector 40 and brushes 42 aremounted to the brush card 34. The brush card 34 includes two pairs ofopenings 43 therethrough. One pair of openings 43 is associated with onechoke 10 for mounting the choke to the brush card 34. Each opening 43 issized to receive an associated attaching structure 20 or 20″ of thechoke 10. Thus, during assembly each attaching structure 20 and 20′ isdisposed through an associated opening 43 with the wound portion 15 ofthe choke 10 being disposed on the first side 36 of the brush card 34.The attaching structures 20 and 20′ are bent generally 90 degrees aboutaxis D (which, as shown in FIG. 1, is parallel to the coil axis A) so asto engage, or at least be adjacent to, the second side 38 of the brushcard 34 thus securing the choke 10 with respect to the brush card 34. Inthe illustrated embodiment, the attaching structures 20 and 20′ are bentoutwardly or away from each other, but it can be appreciated that theattaching structures 20 and 20′ can be bent toward each other to achievethe same securing function.

[0019] The use of the attaching structures 20 and 20′ avoids the needfor separate choke fastening components or a molded brush card, providesa simple attachment of the chokes, and reduces the need forenvironmentally-sensitive solder pastes or adhesives.

[0020] As best shown in FIG. 3, since the end portions 22 are elongated,one of the end portions 22′ is coupled to a terminal 44 of the connector40. In particular, the terminal 44 defines an open channel 48 whichreceives at least a portion of the end portion 22′. The other endportion 22″ is electrically coupled to a brush shunt wire 46.

[0021] The use of elongated end portions 22 of the choke 10 reduces thenumber of electrical connections required on the brush card, eliminatesthe costly manufactured bus bars, and reduces the number of separatemechanical fasteners need on the brush card.

[0022] The foregoing preferred embodiments have been shown and describedfor the purposes of illustrating the structural and functionalprinciples of the present invention, as well as illustrating the methodsof employing the preferred embodiments and are subject to change withoutdeparting from such principles. Therefore, this invention includes allmodifications encompassed within the spirit of the following claims.

What is claimed is:
 1. A choke for suppressing radio-frequencyinterference of a brush-type motor, the choke comprising: a single wirehaving a portion wound about a coil axis to define a plurality of coilsincluding two outermost coils, an attaching structure extending fromeach outermost coil and being generally transverse with respect to thecoil axis, each attaching structure being constructed and arranged to beinserted through an associated opening in a supporting structure and tobe bent so as secure the choke to the supporting structure, and anelongated end portion extending from each attaching structure so as tobe spaced from and generally parallel to the coil axis, the elongatedend portions extending in opposite directions, one of the elongated endportions being constructed and arranged to be directly electricallyconnected to an electrical connector of a motor and the other of theelongated end portions being constructed and arranged to be inelectrical connection with a brush of the motor.
 2. The choke of claim1, wherein a center axis of each elongated end portions is disposed on acommon plane.
 3. The choke of claim 2, wherein at least one of theattaching structures includes a first portion extending transverselyfrom an associated elongated end portion and generally along the commonplane, a second portion extending downwardly and transversely withrespect to the first portion, a third portion extending from the secondportion so as to be generally parallel with the first portion, and afourth portion extending upwardly from the third portion to anassociated outermost coil, the fourth portion being generally parallelwith respect to the second portion.
 4. The choke of claim 2, wherein atleast one of the attaching structures includes a first portion extendingdownwardly and transversely with respect to an associated elongated endportion, a second portion extend transversely from the first portion anda third portion extending upwardly from the second portion to anassociated outermost coil, the third portion being generally parallelwith respect to the first portion.
 5. The choke of claim 2, wherein theelongated end portions are disposed in spaced relation.
 6. The choke ofclaim 1, wherein each elongated end portion extends from an attachingstructure a distance substantially equal to a length of the portionwound about the axis.
 7. A brush card assembly for a d.c. motorcomprising at least one choke comprising: a portion wound about a coilaxis to define a plurality of coils including two outermost coils, anattaching structure extending from each outermost coil and beinggenerally transverse with respect to the coil axis, and an elongated endportion extending from each attaching structure so as to be spaced fromand generally parallel to the coil axis, the elongated end portionsextending in opposite directions, a brush card having first and secondopposing sides and a pair of openings through the opposing sides, eachattaching structure being disposed through an associated opening andbent so as to be adjacent to the second side, with the wound portion ofthe choke being disposed on the first side of the brush card, such thatthe choke is secured to the brush card, a brush mounted on the brushcard and in electrical connection with one of the elongated endportions, and an electrical connector mounted on the brush card, theelectrical connector having a terminal receiving the other elongated endportion of the choke.
 8. The brush card assembly of claim 7, wherein acenter axis of each elongated end portions is disposed on a commonplane.
 9. The brush card assembly of claim 8, wherein at least one ofthe attaching structures includes a first portion extending transverselyfrom an associated elongated end portion and generally along the commonplane, a second portion extending downwardly and transversely withrespect to the first portion, a third portion extending from the secondportion so as to be generally parallel with the first portion, and afourth portion bent to extend upwardly from the third portion to anassociated outermost coil, the fourth portion being generally parallelwith respect to the second portion.
 10. The brush card assembly of claim8, wherein at least one of the attaching structures includes a firstportion extending downwardly and transversely with respect to anassociated elongated end portion, a second portion extend transverselyfrom the first portion and a third portion extending upwardly from thesecond portion to an associated outermost coil, the third portion beinggenerally parallel with respect to the first portion.
 11. The brush cardassembly of claim 8, wherein the elongated end portions are disposed inspaced relation.
 12. The brush card assembly of claim 7, wherein eachelongated end portion extends from an attaching structure a distancesubstantially equal to a length of the portion wound about the axis. 13.The brush card assembly of claim 7, wherein the attaching structures arebent so as extend away from each other at the second side of the brushcard.
 14. The brush card assembly of claim 7, wherein the terminalincludes and opened channel and at least a portion of the elongated endportion is received in the opened channel.
 15. A method of connecting achoke to a brush card assembly, the choke including a portion woundabout a coil axis to define a plurality of coils including two outermostcoils, an attaching structure extending from each outermost coil andbeing generally transverse with respect to the coil axis, and anelongated end portion extending from each attaching structure so as tobe spaced from and generally parallel to the coil axis, the elongatedend portions extending in opposite directions, the brush card assemblyincluding a brush card having first and second opposing sides and a pairof openings through the opposing sides, a brush mounted on the brushcard, and an electrical connector mounted on the brush card, theelectrical connector having a terminal, the method including the stepsof: inserting each attaching structure through and associated opening,with the wound portion of the choke being disposed on the first side ofthe brush card, bending each attaching structure so as to be adjacent tothe second side, thereby securing the choke to the brush card, directlyelectrically connecting one of the elongated end portions with theterminal, and electrically connecting the other elongated end portionwith the brush.
 16. The method of claim 15, wherein the terminalincludes an opened channel and the method includes receiving at least aportion of said one elongated end portion in the opened channel.